-->Plant Ecology and Geography

Water ecological amplitude of Phalaris arundinacea at rhizomatic germination and seedling stage

2016/9/3 0:58:27

We carried out an indoor culturing experiment to cultivate Phalaris arundinacea using rhizome to explore water ecological amplitude at rhizomatic germination and seedling stage. We exposed P. arundinacea to C1(2 ± 0.5)%, C2(10 ± 0.5)%, C3(15 ± 0.5)%, C4(20 ± 0.5)%, C5(25 ± 0.5)%, C6(30 ± 0.5)%, C7(40 ± 0.5)%(water saturation)and C8 flooding(2 cm)for 60 d, and determined the germination rate and various physiological indexes and morphological indexes. The results were as followes:(1)Rhizomatic germination rate of the plants was lowered by drought or excessive saturated of soil water content, but the rhizome still had stronger drought-resistance than seeds. Plant height and aboveground biomass increase firstly and then decreased with the increase of soil water content. The relationship between the plant height and aboveground biomass could be described as an exponential function: y = 0.203 8e^0.0486^x(R² = 0.803 2).(2)The plants could adapt to the stress environment by adjusting the structural features, reducing the size, and decreasing the leaf number and the leaf area. Leaf length, leaf width, leaf number and leaf area showed the similar trend of increasing firstly and then decreasing with the increase of soil water content. When the soil water content ranged between 10%-30%, the water content of plant were able to maintain stability, and then increased with the increase of soil water content.(3)Chl a, Chl b, Car and SPAD contents in young shoots followed the same trend in variation, increasing firstly and then decreasing with the increase of soil water content. But Chl a/b content decreased firstly and then increased, did no differ much in the eight treatments.(4)There is no significant difference of Chl/Car in these treatments. In drought or excessive saturated of soil water content, the plants adjusted the distribution of Chl a and Chl b, raised Chl a /b, maintained Car /Chl, in order to maintain the regular photosynthesis process. Based on the above analysis, quantitive analysis on rhizomatic germination rate, morphological indexes and physiologic indexes by Gaussian Model, it is clear that the water ecological amplitude of P. arundinacea for rhizomatic germination and seedling stage was 7.48%-52.20%, and the optimum water ecological amplitude was 18.99%-40.60%.

Vertical distribution of bryophytes in Yueliang Mountain Nature Reserve

2016/9/3 0:58:27

The vertical distribution law of bryophytes was studied and analyzed by collecting and identifying bryophytes specimens, measuring and analyzing data by SPSS in Yueliang Mountain Nature Reserve, Guizhou, China. The results showed that there were 69 families, 147 genera and 374 species, with obvious vertical bands of bryophytes. The percentage of families, genera and species increased first then decreased along with the increasing of altitude and the dominant families Hypnaceae and Lejeuneaceae, as well as the dominant genera Fissidens, Frullania, Bryum, Cololejeunea and Lejeunea had similar trend. The rock-community and soil-community possessed the most widely distribution, followed by tree- community, while aquatic community had the narrowest distribution, as well as the number of dioecious plant was more than that of tmonoecious plant bryophytes, with the scale 7:3. Many adverse environments made the leaves significantly small, the ratio between leaf length and width significantly increased and the morphology of Entodon macropodus(Hedw.)Müll. ranged from ovoid to egg lanceolate, as well as the capsula greatly significantly shortened, the diameter of spore, the number of spores gradually reduced and seta gradually became significantly long for the spread of spores, which showed the adaption of bryophytes. This paper provides the basic information for the further study of the distribution and environment adaption of bryophytes.

Two newly recorded genera of angiosperm from Guangxi

2016/9/3 0:58:27

In the Pilot Work of the Fourth National Survey on Chinese Materia Medica Resources, we collected many herbarium specimens. Through detailed identified and consulted literatures, we identified that there were two new recourded genera of Guangxi in these specimens. The genus Carlemannia Benth., leaf opposite, ovary inferior, estipulate, stamens only two, similar to Rubiaceae, but there were significant differences. Therefore, it was previously putted in Rubiaceae and Caprifoliaceae, most recently this genus with Silvianthus form a new family Carlemanniaceae, only three spicies in this genus. This family distributed along the Himalayas to Burma, North Vietnam and South China, one species Carlenannia chinenesis Hook. f. in Southeast Tibet, South Yunnan, Northwest Guangxi. Commicarpus is a genus producing in the areas of tropical, about 25 specieses in the world, main in tropical southern area of Africa and the Arabian Peninsula, in South Asia, Southeast Asia and Mexico to tropical America also has some specieses. Two specieses distributed in China, only Commiaicarpus chinensis(L.)Heim. in Guangxi. This species is distributed from the South Asian subcontinent east to Indochina, Malay Peninsula, and north to the Xisha Islands, Hainan Island, and the nearby Guangzhou of China. It is firstly recorded in Guangxi Fengshan and Lingyun counties.

Responses of soil microbial biomass, community structure and soil enzyme to below-ground carbon change in the warm-temperate forest ecosystem

2016/8/18 11:06:30

This study focuses on the controlling mechanisms of soil microbial community structure and function to the change of below-ground carbon inputs through root-trenching experiments in a typical forest ecosystem of the subtropical and temperate transitional zone in China. By combining field investigations and manipulation experiments, phospholipid fatty acids(PLFAs)and activities of soil extracellular enzymes were studied as indicators of soil microbial community structure and functioning. We also studied the response characteristics of soil microbial biomass, community structure and activities in below-ground carbon inputs. The results showed that soil microbial biomass carbon in root-trenching plots reduced significantly in an age sequence of Quercus aliena forest(40-year-old, 80-year-old, and >160-year-old). Integrated over the entire experimental period; the mean difference of soil microbial biomass carbon in root-trenching plots were reduced between -8.72% and -5.72%, and the highest reduction was in the 80-year-old forests, whereas the lowest decline was in the 160-year-old forests. The variation of soil microbial biomass nitrogen was similar with the changes of soil microbial biomass carbon in the forest stands of similar age, but compared with the control plots, it did not decrease significantly. In addition, compared with the control plots, the soil microbial biomass carbon and nitrogen in all forest stands increased after trench for 2 to 4 m. The root-trenching can produce different effects on soil microbial community structure in all forest stands, the response of microbial communities to the change of below-ground carbon input in 40-year-old forests were higher than the other two age groups. The relative abundances of saprotrophic fungal community in root-trenching plots was declined sharply in all stands, and it reduced significantly in 80 and 160-year-old forests compared to control. Other communities like bacteria, actinomycete and arbuscular mycorrhizal fungi changed slightly in all forest stands; the hydrolase activities(i.e. β-1,4-glucosidase and β-1,4-N-acetylglucosaminidase)in root-trenching plots decreased remarkably in the 40, 80 and 160-year-old stands, but the oxidase activity(i.e. phenol oxidase and peroxidase)was not diminish in all plots except 160-year-old stands. The root-trenching treatment had no obvious influence on soil moisture and soil temperature. By addressing the response characteristics of soil microbial biomass, community structure and function on the plant root carbon input, this study sheds light on the trends of soil microbial structure and function change under the context of global climate change. This study shows the need for more accurate prediction trends of forest soil carbon in the future.

Interspecific associations between south subtropical forest plant community species in Daqingshan of Guangxi

2016/8/18 11:06:30

The natural secondary forest in Southwest Guangxi is rich in typical forest communities; however, little is known about the inter specific associations of the dominate species. Hence, our objective was to investigate how the dominant species in the communities interact with each other. We sampled 1 km² in the natural secondary forest, selected 17 tree species, 8 shrub species and 12 herb species according to importance values and studied inter specific associations by using variance ratio(VR)analysis and χ²-tests, percentage co-occurrence(PC)and association coefficient(AC). There was a significant positive correlation of overall association among trees, an insignificant negative correlation among shrubs, and an insignificant positive correlation among herbs. χ²-tests showed that there was a positive association for 81 pairs and a negative association for 19 pairs and 5 pairs did not have a relationship among trees. There was a positive association for 14 pairs and a negative association for 12 pairs and 2 pairs did not have a relationship among shrubs. A positive association was found for 32 pairs and a negative association for 24 pairs and 5 pairs did not show a relationship among herbs. The main tree species were connected more closely whereas main shrub species association was loose and main herb species association is weak. The main causes for different associations were assumed to be ecological habits, community succession stage among others. In the future,the management and protection of the natural environment should be more strengthen,if necessary,manual intervention may be appropriate in order to promote the natural secondary forest succession. The research will provide the information only for understanding the current situation and trends in its plant community succession,but also for the future research on its plant community succession regular and the protection of its species diversity.

Comparing the water use efficiency of plants in different types of rubber-based agroforestry ecosystem in Xishuangbanna, Southwest China

2016/8/18 11:06:30

A huge area of rubber(Hevea brasiliensis)monoculture in Xishuangbanna, Southwest of China have caused many ecological and environmental problems now. In order to coordinate these problems and local economic development, agroforestry ecosystem as ecologists'common advise has been considered the best way to solve above problems. However, little information about rubber's water use efficiency is known in different agroforestry ecosysterns. For this reason, we measured soil water content, the shoot predawn and middy water potential, and the leaf δ¹³C of Hevea brasiliensis as well as its interplant in four rubber-based agroforestry ecosystems(Hevea brasiliensis—Theobroma cacao agroforestry ecosystem, Hevea brasiliensis—Camellia sinensis agroforestry ecosystem, Hevea brasiliensis—Coffea arabica agroforestry ecosystem, Hevea brasiliensis—Flemingia macrophylla agroforestry ecosystem)and one rubber monoculture which was locatd at Xishuangbanna Tropical Botanical Garden in Southwest Yunnan Province, China in August 2013(rainy season), November(conversion of the rainy and dry seasons)2013, January 2014(foggy season)and March 2014(pronounced dry season). We aimed to apply stable carbon isotopes techniques in the study of the water use efficiency of Hevea brasiliensis in those rubber-based agroforestry ecosystems, and thus to select optimal agroforestry ecosystems which can use water reasonably and effectively. Depending on the multivariate statistical analysis, the results were as follows:(1)The average leaf δ¹³C of Hevea brasiliensis in those agroforestry ecosystems(except for Hevea brasiliensis—Coffea arabica agroforestry ecosystem )were higher than that in rubber monoculture;(2)The soil water content in Hevea brasiliensis—Flemingia macrophylla agroforestry ecosystem was always higher than others during the research period(P<0.01);(3)Despite the soil water content of Hevea brasiliensis—Camellia sinensis agroforestry ecosystem was the second highest, but it was the most stable one which change small with season;(4)The water use efficiency of Hevea brasiliensis—Coffea arabica agroforestry ecosystem was the most stable, and it was the highest one in despite of the chilling injury at the end of 2014;(5)As well as the rubber monoculture, Hevea brasiliensis—Theobroma cacao agroforestry ecosystem did not play a significant role during the whole period, and it expressed many characteristics like the rubber monoculture. All above results indicated that the agroforestry ecosystem(except Hevea brasiliensis—Coffea arabica agroforestry ecosystem)could alleviate the water stress suffered by Hevea brasiliensis in the pronounced dry season. Not only could they keep higher growth and yield than rubber monoculture, but they also could make sure that the Hevea brasiliensis can resist the burst weather disaster at the same time.The results provides the relative theory and reference to support and guide the construction of environmentally-friendly rubber plantation.

Estimating the carbon storage of Fuyang forest ecosystems based on InVEST model

2016/8/18 0:00:00

The forest ecosystem carbon storage was visually quantified, and its spatial distribution was identified, based on remote sensing images data on forest resources and ArcGIS 10.0 software, Fuyang City as a case that belongs to the typical subtropical climate, making use of InVEST-Carbon models to estimate carbon stocks of the Fuyang forest ecosystems. The results showed that there were obvious regional differences about the distribution of carbon storage in Fuyang forest ecosystems from east to west which showed high-low-high-low distribution. The total carbon storage of Fuyang forest ecosystems was 26.743 7 million t. And it valued 3 990.421 million yuan. The average carbon density distribution of various kinds of forest type was: evergreen broad-leaved forests > coniferous and broad-leaved mixed forests > bamboo forest > masson pine forests > fir forests. It was roughly identical to the carbon density distribution in the major types of the Ecological Public Welfare Forest in Zhejiang Province. And we found that its total forest carbon density was about 180.75 t·hm^-2. It exceeded the Ecological Public Welfare Forest in Zhejiang Province and all over the country in carbon density. The calculated carbon density was not so far from that computed by the relation between the biomass and volume based on forest inventory data that was 28.3780 million t. The InVEST-Carbon model could be applied to the estimation of the overall forest ecosystem carbon storage. By the research it implied that the evaluation results of the InVEST model were clear and intuitive. The quantitative forest carbon was shown in form of a map by importing less data. The InVEST model could be used to the prediction of the future or multiple simulations, etc. It provides the decision-making information of the natural resources management for the government, non-profit organizations and companies. It can be an effective tool for gain and loss of balance assessment with the multifunction and modularized designation.

Evaluation of ecosystem services in the small-scale forest in suburban

2016/8/18 11:06:30

According to the principle of index selection and related research methods, in reference to the previous studies, it has constructed the assessment index system of the small scale forest ecosystem service function. In order to evaluate the value of small-scale forest ecosystem services in suburban of Liuzhou City, we selected Shatang forestry farm as study area. It has constructed the assessment index system of the small scale forest ecosystem service, 7 respects of providing forest by-product, water supply, carbon fixed and oxygen released, biodiversity conservation, environmental purification, soil conservation, forest tourism, forest nutrition storage was evaluated by 13 index. The forest resource survey data in 2009a, long-term observation data from forest ecosystem research station and other public social-economy statistical data were used to work according to the method for assessment of forest ecosystem services in China(LY/T1721-2008). The results showed that the matter quantity of water supply was 5 051.04 m³·hm^-2·a^-1, the matter quantity of soil fixation was 29.30 t·hm^-2·a^-1, the matter quantity of nutrient conservation was 1.09 m³·hm^-2·a^-1, the matter quantity of carbon fixation and oxygen released 5.27 m³·hm^-2·a^-1 in Shatang forestry farm. The annual average value of forest ecosystem services in the Shatang forestry farm was 78 077 001 yuan per year. The annual mean value of forest ecosystem services was 79 630 yuan per hectare per year. The value of seven service functions were ranked as follows: water supply(52.02%)> carbon fixation and oxygen release(22.36%)> biodiversity conservation(12.61%)> environmental purification(5.06%)> soil conservation(3.84%)> forest tourism(3.09%)> forest nutrient storage(1.03%). The per unit area value of ecosystem services from varieties of trees were ranked as follows: Eucalyptus forests(104 673.43 yuan·hm^-2·a^-1)> Other broad leaved forests(95 538.66 yuan·hm^-2·a^-1)> Economic forests(69 537.58 yuan·hm^-2·a^-1)> Pin forests(69 433.52 yuan·hm^-2·a^-1)> Fir forests(58 820.11 yuan·hm^-2·a^-1). The annual mean amount of water supply and carbon fixed in Shatang forestry farm were greater than the average values of Guangxi Zhuang Autonomous Region, and the same to the value in forest tourism. The research indicated that the ecosystem services in small-scale forest in suburban areas played an important role in local forest ecosystem services. It provides the scientific basis for the construction of ecology civilization in Liuzhou City because it is conducive to unify with ecological benefit as the first, with social benefit as the core,with environmental benefits as the premise, with economic efficiency as the goal of forest ecosystem.

Distribution and community characteristics of threatened seagrass Halophila beccarii in Dongzhai Harbor, Hainan

2016/8/18 0:00:00

Recent mangrove surveys have discovered a seagrass bed of Halophila beccarii within Dongzhaigang National Natural Reserve, Hainan that have not previously been reported. The distribution, basic biological traits of the seagrass bed and associated habitat(sediment and sea water)were studied in the paper. H. beccarii is among one of the ten seagrass species which are at elevated risk of extinction in the world, and it was listed as ‘Vulnerable' by the International Union for Conservation of Nature(IUCN)under criterion B2. It is generally hard to be found in the field due to its very tiny leaves and its shoots are easily buried by sediment. In addition, this species has a very narrow, restricted depth range right at the intertidal zone(usually mud flat or seaward mangrove areas), where is submersed tidally every day. Moreover, rapid population turnover and low awareness of seagrass do not facilitate the discovery of this species in China. Until today, very limited H. beccarii resources have been reported along the coast of Fujian, Taiwan, Guangdong, Hong Kong, Guangxi and Hainan, with an estimation of total area of less than 200 hm² in China. In this study, we used a hand-hold GPS to map the extent of seagrass distribution in the study area. Besides, we sampled seagrass plants, associated sediment and seawater for analysis in the lab. Compared with other H. beccarii sites in China, the area in Dongzhaigang was relative big, with a total area of 15.4 hm² and intermediate density of(10 394 ± 576)shoots·m^-2, ranking the second largest H. beccarii bed in China according the published data. However, the biomass(9.225 ± 1.151 gDW·m^-2)and percent coverage(5.0% ± 1.1%)at this site was very low partly due to its pretty small leaf [leaf length:(4.83 ± 0.87)mm; leaf width:(1.44 ± 0.21)mm]. The ratio of above- to below-ground biomass was also very low(0.34), with(2.339 ± 0.245)gDW·m^-2 of above-ground biomass and(6.886 ± 1.055)gDW·m^-2 of below-ground biomass. No flower and fruit of the plant was found during our survey, but an intermediate density(2 105 ± 664 seeds·m^-2)of seeds in the sediment was found. The organic carbon content and bulk density of sediment in the study area was(2.08 ± 0.13)% [0-10 cm:(2.42 ± 0.03)%; 10-20 cm:(2.17 ± 0.03)%; 20-30 cm:(1.65 ± 0.20)% and(0.98 ± 0.01)g·cm^-3. 0-10 cm:(0.93 ± 0.01)g·cm^-3; 10-20 cm:(0.97 ± 0.01)g·cm^-3; 20-30 cm:(1.02 ± 0.02)g·cm^-3] respectively. In addition,(6.67 ± 0.24)‰ of salinity,(7.33 ± 0.03)of pH,(-1.53 ± 1.85)mV of oxidation reduction potential(ORP)and(6.65 ± 0.31)mg·L^-1 of dissolved oxygen(DO)of overlying water in the study area was measured in situ. On the other hand,(1.90 ± 0.03)mg·L^-1 of total nitrogen content(TN),(0.13 ± 0.01)mg·L^-1 of total phosphorus content(TP)and(5.89 ± 0.06)mg·L^-1 of organic carbon content(C_org)of sampled-seawater during high tide in the study area was detected in the lab. A certain level of pollution in sea water of the site was demonstrated, which was consistent with the previous research in the same study area. We suggest that the seagrass plants and their associated habitats should also be listed in the key protection objects by the Management Bureau of Dongzhaigang National Natural Reserve besides mangrove ecosystem.

Effects of ecological factors on anther dehiscence of Paris polyphylla var. yunnanensis

2016/10/30 19:46:39

Paris polyphylla var. yunnanensis to Trilliaceae plants, have a very high medicinal value, because of the traditional medicinal part slow growth and low fertility. Due to the excessive excavation of the resources of wild P. polyphylla var. yunnanensis excessive excavation, the resource is dried up. Anther dehiscence is a multistage process involving localized cellular differentiation and degeneration, combined with changes to the structure and water status of the anther to facilitate complete opening and pollen release. Jasmonic acid has been shown to be a critical signal for dehiscence, although other hormones, particularly auxin, are also involved. Anther dehiscence is affected by light, temperature, humidity and other ecological factors. P. polyphylla var. yunnanensis of anther in the entire flowering cracking-closure phenomenon, anther effective closure should protect pollen, for extend the service life of pollen, the increase of a male fitness adaptation mechanism. We observed the effects of ecological factors, light intensity, temperature, humidity changes in anther dehiscence process of P. polyphylla var. yunnanensis. The effects of ecological factors such as light intensity, temperature, relative humidity and light quality on the anther dehiscence of P. polyphylla var. yunnanensis were studied by comparing experiments and orthogonal experiments. The main experimental results were as follows: Light intensity and temperature increased, humidity droped in the process of anther dehiscence of P. polyphylla var. yunnanensis; Temperature was the main factor affecting anther dehiscence, temperature increasing encouraged anther opening and temperature decreasing encouraged anther closing; Dark and high humidity delayed anther dehiscence, but it did not prevent anther dehiscence; Low temperature kept anther remaining closed for a long time and increasing light intensity could reduce the temperature limiting anther dehiscence. The study explains the relationship between environmental factors and the phenomenon of anther opening in the daytime and closing at night,and provides the information for cultivation and breeding of P. polyphylla var. yunnanensis.

Relationship between stem flow of flowering jujube and meteorological factors

2016/10/30 19:46:39

Aksu area of irrigation water resources use rate is relatively low, the irrigation, drip irrigation, and arid environment and water resource shortage have become the main factors of constrainting local jujube planting industry development, therefore, it is urgent to find new water-saving irrigation method. We studied the relationship between jujube stem flow variation by different irrigation methods and meteorological factors, continuously monitored stem flow rate with Flow-32 packaged stem sap flow gauge produced by Dynamax company. The results showed that the change of stem linger under two kinds of irrigation methods presenting the obvious diurnal variation law of stem flow rate were unimodal curve and stem flow activities at night phenomenon was obvious. Stem flow morning starting time of was 0.5 h earlier than that of W2, W1 and W2 jujube stem flow were small amplitude “peak population” before and after the peak,W1 and W2 peak time were respectively 13:30-14:30 and 13:00-14:30, peak value were 2 133.33-2 724.93 g·h^-1 and 2234.11-2 689.40 g·h^-1. Stem flow daily cumulative quantity change process curve were “S” shape, but W1, stem flow was greater than the total W2; Stem flow rate variation curves of solar radiation and temperature showed a positive correlation, a negative correlation with air humidity, poor correlation with wind speed; The apparent wave solar radiation trends under two irrigation methods and stem the flow curves presented similarities and differences, the start time was 0.5 h earlier than that of W1, 1 h earlier than that of W2, but the peak time was later than W1 and W2. Through correlation analysis, we deduced that the solar radiation main influencing factors, and set up two kinds of irrigation mode flow rate and meteorological factors of multivariate linear model, through the regression coefficient and correlation coefficient test, W1 and W2 multiple linear regression equation reached the significant level. This study provides scientific information for the practicality and superiority of new irrigation method W1.

Characteristics of soil respiration components in the Quercus aliena var. acuteserrata forest chronosequence

2016/10/30 19:46:39

The forest age as a factor affecting soil respiration is one of the hot issues in the carbon cycle, and forest age also plays an important role in simulating succession and monitoring the long-term carbon dynamic. We investigated soil respiration dynamics and characteristics in warm-temperate oak chronosequence in China, and measured soil respiration with a Li-Cor infrared gas analysis. We studied the effects of forest age on soil respiration flux and different components of Quercus aliena. The results showed that the seasonal patterns of soil respiration among the age classes of Q. aliena var. acuteserrata forest(40 a, 80 a, >160 a)and different components showed the obvious seasonal dynamics, and occurred as a unimodal curve. Soil respiration rate had a significantly exponential correlation to 5 cm soil temperature. This also could be explained by the effects of temperature on the activity of soil organisms. The exponential equations of soil temperature and soil respiration accounted for more than 80% of the variations in soil respiration rate. There was no significant variation in soil respiration and its components among different forest ages, and the sensitivity of soil respiration to temperature in different age chronosequence and soil components of Q. aliena var. acuteserrata forest also had no significant difference, which might be explained by the fact that there was no significant difference among the age classes of Q. aliena var. acuteserrata forest in soil properties, forest productivity and micro-environmental conditions. The cumulative soil respiration in treatment with doubled litter was significantly(P<0.05)higher than that of other components, which indicated that more litter could provide more abundant nutrient for the activity of soil microorganisms. There were also correlations of cumulative soil respiration with soil organic carbon(SOC), fine root biomass(FR)and microbial respiration(MR), which indicated that the soil properties and underground metabolism could well enough to explain the pattern of soil respiration among the age classes of Q. aliena var. acuteserrata forest in this region.

New records of lycophytes and ferns from Shandong Province

2016/10/30 19:46:39

Four species, one variety and one form of lycophytes and ferns are reported for the first time from Shandong Province. They are Selaginella nipponica Franch. et Sav., Polystichum hancockii(Hance)Diels, Cyrtomium yamamotoi Tagawa, C. yamamotoi var. intermedium(Diels)Ching et Shing ex Shing, C. fortunei J. Sm. f. polypterum(Diels)Ching, and Lepisorus ussuriensis var. distans(Makino)Tagawa respectively. The spore ornamentations are examined by means of scanning electron microscopy(SEM)to facilitate the palynology identification of these species.

Structure and dynamic characteristics of wild longan population in Dongfang City, Hainan

2017/4/20 23:46:53

Wild longan, the wild population of longan, is an important gene bank for the betterment and innovation of longan variety. In order to reveal the population distribution and the trend of population dynamics of wild longan, the population diameter structure, static life table, and survival curve of wild longan population were studied based on the field survey in Dongfang City, Hainan Province. The results were as followers:(1)Wild longan of communities of vegetation types which can be divided into monsoon forest, tropical rainforest and the transitional zone between monsoon forest and tropical rainforest.(2)The population size of wild longan was the largest in tropical rainforest, medium in the transitional zone and smallest in the monsoon forest.(3)The survival curve of the wild longan population showed that they approached a Deevey-II type, and the mortality rate in different size classes was similar.(4)A dynamic index of population size structure showed that their population are stabled in the monsoon forest and tropical rainforest, but its population of the transitional zone tended to be stabile.(5)Time-sequence models for wild longan population predicted that the number of different size classes will increase after two and four years. As a result, wild longan populations under monsoon forest tended to increase the number of individuals from the Age Class V later, while the rainforest and the transitional zone is after Age Class IV. From the entire stages of development of wild longan population, the number of the three vegetation types of wild longan were relatively abundant in young period, the population had a sufficient reserve resources, individual number of the medium tree and the big tree can be replenished in existing foundation. The wild longan population of Dongfang City can have a better recovery potential, as long as continue to maintain the current distribution of wild longan plants and habitat patches and take effective protective measures. The innovation of this paper is to analyze from different vegetation types of dynamic structure of wild longan population in Dongfang City, and this study provides information for population characteristics at different vegetation types of wild longan resources.

Pollination biology of Aspidistra retusa

2017/4/20 23:46:53

Aspidistra Ker-Gawl.(Asparagaceae)is one of the largest genera in monocots, flowers of most Aspidistra species grow on the ground and are even buried in leaf litter, inaccessible to many potential pollinators, and pollination biology of Aspidistra has been poorly studied. Aspidistra retusa is a typical species with higher stamens than pistil in floral structure, distributed only in Guangxi, China. In order to reveal the significant pollination mechanism, we focused on its floral morphology, reproductive biology and pollinator behavior. The results indicated that A. retusais was a self-incompatible species and pollen vector was necessary for fruit set. Cecidomyia sp.(Cecidomyiidae, Diptera)served as the sole pollinator and A. retusa provided suitable mating site and abundant pollen for the adult of gall midgeand protection for the hatching of zygote and the development of larvae as rewards. This study provided the first field observation on the pollination biology of the genus Aspidistra distributed in China and verified vividly the previous speculation of gall midge pollinating for Aspidistra. However, Aspidistra plants with species diversity, there should be more pollination patterns, still need further research.

Coenological characteristics of Pseudotsuga sinensis forests in Qizimei Mountains Nature Reserve

2017/4/20 23:46:53

Pseudotsuga sinensis is the second-class state protected plant, it is China's unique tertiary relict precious species and mainly distributed in subtropical mid-mountain zone. In order to better protect the remnant and endangered P. sinensis, we investigated original P. sinensis forests in Qizimei Mountains Nature Reserve using Braun-Blanquet phytosociological and typical plots methods and analyzed their community characteristics. The results showed that the P. sinensis community contained 52 vascular plants belonging to 24 families and 38 genera in 2 300 m² sample plots. The P. sinensis community was mainly composed of Ericaceae, Leguminosae, Aaliaceae, Fagaceae species and so on. Moreover, the life form composition of the P. sinensis community revealed that Phaenerophytes had an absolute dominance, besides, Phaenerophytes and Hemicryptophytes accounted for 76.9%, 13.5% respectively. Chamaephytes and Geophytes were fewer plants, occupied small proportion. Therefore, the life form spectrum was roughly “L” type. The analysis of community importance values showed that the P. sinensis was absolutely dominant in the tree layer and its importance value was 53.6, and it was constructive species in the community. Moreover, the Quercus phillyreoides and Pyrrosia lingua were the dominant species in shrub layer and herb layer, and their importance values were 24.0, 54.8 respectively. Based on our analysis, we found that the species diversities indexes of the Pseudotsuga sinensis community were low in general. In addition to species evenness index, species dominance index, species diversity index and species richness index had the same patterns: species diversity index in shrub layer was the highest, the tree layer was the second, and the herb layer was the lowest. Based on the topographical conditions, we knew that the species diversity index exhibited that the upper slopes was greater than the ridges regularly. Population age structure showed that the P. sinensis had an L-shaped distribution, which implied the community of P. sinensis was an increasing population type. So we can conclude that P. sinensis will always be a dominant species in Qizimei Mountains Nature Reserve in a certain time. Furthermore, with the appearance of forest gaps, the P. sinensis community can be updated continuously.

Analysis on community stability and inter-specific correlations among dominant woody populations of the endangered plant Sinojackia rehderiana communities

2017/4/20 23:46:53

Populations of Sinojackia rehderiana are highly threatened and have small and scattered distribution due to habitat fragmentation and human activities. In the present study, we selected 24 dominant species according to frequency and studied interspecific associations and correlations usingvariance ratio(VR)analysis of the overall association, x² and W tests, association coefficient, and percentage co-occurrence based on 2×2 contingency tables of species presence/absence data. In addition, we tested the level of community stability by using the Godron stability analysis. The results showed that the total community association of variance ratio was greater than one; the test satistic W was lower than x²_0.05(50), indicating that the species in the overall community were positively associated, but this association was not significant. When species pairs were analyzed, the associations of S. rehderiana with other plant species had no significant inter-specific associations and inter-specific correlations tended to be independent and random. Godron stability analysis showed that the ratios of cumulative inverse of species number to cumulated relative frequency was 35/65, distinctly different from 20/80. The ratios was far from the stability point, indicating that the whole community was unstable. The results indicated that the S. rehderiana community was not stable, and stronger protective measures were required. Therefore, species with positive associations should be chosen in situ and ex situ conservations in order to establish a suitable environment for S. rehderiana, and make its populations more stable.

New records of ferns from Guangxi, China(Ⅱ)

2017/4/20 23:46:53

Seven species of ferns are reported as new records from Guangxi, China. They are Botrychium virginianum, Coniogramme serrulata, Pteris xiaoyingae, Diplazium ovatum, Bolbitis hainanensis, B. hekouensis and Dryopteris juxtaposita. The citations of specimen and distributions have been enumerated in this paper.

Analysis on vertical distribution pattern of flora of seed plants in Kuche

2017/4/20 23:46:53

Kuche is located in the middle of the Tianshan Mountains in Xinjiang,the northern margin of the Tarim Basin. In terms of geographical division, the vegetation in this region belongs to the warm temperate shrub and subshrub desert area of Xinjiang. Based on field studies and relevant literature, the vertical distribution characteristics of the flora in Kuche were systematically analyzed. The results showed that there were approximately 960 species of seed plants belonging to 78 families and 376 genera in Kuche. Among these, there were nine species of Gymnosperm belonging to three families and three genera. There were 951 species of Angiosperm belonging to 75 families and 373 genara. The total number of families indicated that the highest peak at the elevation with 1 600-1 800 m. The total number of genera indicated that the highest peak at the elevation with 1 800-1 900 m. The total number of species showed that the highest peak at the elevation with 1 900-2 000 m, there were 59 families, 230 genera, 478 species. From the altitude with 2 200-2 300 m, the number of seed plants family, genus, species showed a decreasing trend with increasing altitude, and the distribution curve showed an unimodal peak distribution structure. North temperate elements were dominant in family and genera floristic composition. In vertical gradients, a peak of temperate distribution type appeared in 1 800-1 900 m(including 20 families), from the altitude gradient with 2 800-2 900 m showed a decreasing trend, to 3 600-3 700 m was the lowest(including six families); The temperate distribution peak of the genus appeared in 1 900-2 000 m, and then decreased with the increase of altitude. This study is very important for the characteristics of the altitude gradients on the flora of seed plants of Kuche Mountain in the area of plant germplasm resources and ecosystem diversity, and plant resources of domestication, cultivation and utilization.

Impact factors of the total flavonoid contents in Guizhou miao medicine Laportea bulbifera based on grey correlation analysis

2017/4/20 23:46:53

The total flavonoids content of 42 groups of Guizhou miao medicine Laportea bulbifera were analyzed and determinated by AlCl₃colorimetric. The ammonium nitrogen, available phosphorus, available potassium, pH and water were determinated in the soil by soil nutrients tester and the origin of geographical climatic factors of L. bulbifera from different producing areas were consulted. In order to analyze the total flavonoids contents of different germplasm resources and impact factors by grey correlation degree analysis, geographical climate factors were determinated by the closed meteorogical department who had been inquired data and GPS, combined with the ISSR results of genetic diversity of 42 groups with the above measured data. The result revealed that the flavonoid contents of L. bulbifera in 42 groups of different germplasm resources was at 0.42%-2.16%, the average recovery rate was 97.86% and RSD was 1.5%, respectively. Frostfree period and the Shannon information index I were the biggest factors with the flavonoid contents in the environment factors and genetic factors. And the biggest correlation degree was Shannon information index I(r=1.03)and the smallest was the soil pH(r=0.49)in all of correlation degrees. It could be judged that genetic factor had more influence on the quality of medicinal materials L. bulbifera than environmental factor. The results provide the reference for choosing good germplasm resources and change the wild to the domestic.

Characteristics of the accumulation of heavy metals in the leaves of six common green tree species and its correlation with environment factors in Hangzhou City, China

2017/4/20 23:46:53

In order to detect the heavy metal accumulation ability and the effects of environmental factors on the green tree species leaves, six common green tree species were selected for analyzing six heavy metal elements(Pb, Cd, Cr, Cu, Ni and Zn)concentrations in samples. Three areas were chosen for this research in Hangzhou, China, two industry areas for heavy metal pollution treatments and one natural area for control. Afterwards, leaf, soil and dust fall samples were collected to test the six heavy metal element concentrations using the element analyzer(ICP-AES). The results were as follows:(1)According to the accumulation factors and correlation indexes, we suggested that heavy metal concentrations in the leaves from pollution areas were obviously higher than those in the control. Generally, Zn accumulated the highest concentration in those plants, followed by Pb, and Cd of the lowest. However, different species had inequable abilities on heavy metal accumulation. We infered that Ilex cornuta could be a bio-monitor on Cd, Pb. Juniperus chinensi, Camellia japonica and Magnolia grandiflora could be indictors on Cu, Ni and Zn, respectively.(2)The correlation and regression factors of the six heavy metal concentrations between three collecting areas and leaf samples showed that the heavy metals absorbed in leaf samples had more positive correlation with dust from atmosphere than that from the soil samples. Therefore, it is reasonable and scientific that these trees could be selected as accumulators and bio-monitors of the atmospheric heavy metal pollution. The results provides important references on the indictors and bio-monitors searching about the atmospheric heavy metal pollution.

C, N and P ecological stoichiometry of two bryophyte plants in Baotianman Nature Reserve

2017/3/8 14:17:08

In order to explore adaptation mechanism on the bryophyte plants in Baotianman Nature Reserve, our research determined the ecological stoichiometry characteristics of Thuidium cymbifolium and Mnium immarginatum and revealed the relationships of these nutrient contents with soil nutrients along altitudinal gradients. Our results suggested that the contents of C, N and P in both species were ranged from 46.81% to 49.09% for C, 0.21%-0.25% for N, 0.02%-0.08% for P, respectively. There existed higher variability among different altitude gradients, Thuidium cymbifolium differed significantly for C and N contents, and Mnium immarginatum differed significantly in N and P, while only N exhibited a significant decreasing trend with increasing altitude. The C, N, N:P and C:P of soil exhibited an increasing trends with increasing elevation, which were different from soil P and C:N. The content of C in Thuidium cymbifolium increased with the increase of soil C, while Mnium immarginatum decreased; the content of N in both species exhibited the same phenomenon with former; the N:P showed different trends between two species, the N:P significantly decreased with soil P in Thuidium cymbifolium, while Mnium immarginatum was opposite. Moreover, the mean of leaf N:P was 8.51, which indicated that both of two species were limited by soil N content. These results suggested that two bryophyte species had different utilization ways on soil P element, and the growth of the bryophyte plants in Baotianman Nature Reserve were suffered from N limitation along the altitudinal gradients.

Effects of soil moisture on the ecophysiology of moso bamboo (Phyllostachys edulis)in upper reaches of Lijiang River

2017/3/8 14:17:08

There is a large area of moso bamboo plantation in upper reaches of Lijiang River, where it is the most southern moso bamboo plantation area in China. Seasonal drought occurs frequently in this area which may influence on ecophysiological strategy of moso bamboo. In this paper, we simulated rainfalls which might lead to soil moisture change, thereby to investigate the response of gas exchange of moso bamboo. We made five water treatments: CK. no rainfall and no plastic cover(PC); A. no rainfall but with PC; B. 5 mm rainfall with PC; C. 10 mm rainfall with PC; D. 20 mm rainfall with PC)in bamboo community, and one treatment(natural condition)with native plant Schima superba for comparison. The results showed that simulated rainfall causing soil moisture increase, which resulted in moso bamboo leaf water potential and chlorophyll change. Water potential of the sampled moso bamboo leaves decreased during day time, and could increase again to the level of predawn by the evening. Comparing to other treatments, in Treatment C, water potential decreasing value from predawn to noon was the least, while chlorophyll concentration was the highest. In this most southern area, photosynthetic productivity of our moso bamboo was low compared to other references. Under small water deficiency, moso bamboo leaf might present a high net photosynthesis rate(P_n), high transpiration(Tr)and low water use efficiency(WUE), while under saturated and prolong soil water and low soil water condition, it presented a low P_n and low Tr, but high WUE. P_n and stomatal conductance(Gs)of moso bamboo presented a closely positive correlation indicating P_n was regulated evidently by stomatal. Meanwhile, Tr and water potential at noon presented a negative correlation(binomial function)demonstrating that soil water influencing on moso bamboo leaf water concentration and transpiration. When water deficiency, P_n was regulated mainly by stomatal, but when water saturated and prolong, decreasing of P_n might be due to mutual influence by Gs decreasing and the decline of photosynthetic capacity of mesophyll cells. Therefore, sever water deficiency and over water may result in a negative effect on ecophysiology of moso bamboo. Comparing to native broad evergreen leaf species S. superba, moso bamboo has a higher P_n, and consumes much more water at the same time.

New records of angiosperms in Gansu Province

2017/3/8 14:17:08

One genera belonging to Scrophulariaceae and five species belonging to five families(Scrophulariaceae, Magnoliaceae, Polygonaceae, Elaeagnaceae and Liliaceae)of angiosperms are reported for the first time in Gansu Province. They are Limosella Linn., Limosella aquatica Linn., Michelia wilsonii Finet et Gagnep., Polygonum divaricatum L., Hippophae goniocarpa Y. S. Lian et al. ex Swenson & Bartish and Polygontum qinghaiense Z. L. Wu et Y. C. Yang, respectively, among which Michelia wilsonii Finet et Gagnep. is one of the second-class protected wild plants in China.

A new combination of Phyllolobium (Leguminosae)from China

2017/3/8 14:17:08

Twenty combinations have been made for genus Phyllolobium when those species of subgenus Pogonophace were separated from Astragalus(Leguminosae). The former A. tribulifolius and A. tanguticus were included within the same combination Phyllolobium tribulifolium (Bunge)M. L. Zhang & Podlech. Based on the analyses of morphological characters and their distribution patterns, Astragalus tanguticus could be clearly distinguished from A. tribulifolius. Therefore, a new combination was made for this former Astragalus species as Phyllolobium tangutica(Batalin)Y. Kang & M. L. Zhang.

Gastrodia punctata Aver., a newly recorded species of Orchidaceae from China

2017/3/8 14:17:08

Hainan is the tropical island of China which is remarkable for its rich plant resources. During our field trips to Hainan Bawangling National Natura Reserve, Gastrodia punctata Aver., a newly recorded species of Gastrodia from China, was discovered and here reported. This species was previously considered as endemic to Vietnam. Its Chinese epithet was entitled by the meaning of specific epithet and morphological characters. It could be identified from other species of this genus by the brown sepals with numerous lager white spots, four keels on the lip and the falcate stigma located at the base of column. In this paper, its Chinese description, color illustrations, distribution and conservation status were provided as well.

Carbacanthographis (Graphidaceae), a lichen genus new to Guangxi

2017/3/8 14:17:08

The lichen genus Carbacanthographis is reported as new to Guangxi, characterized by the closed disc, carbonized exciple, labia covered with a distinct white pruinose layer, warty periphysoids, and I- or weakly I+, muriform or trans-septate ascospores. The species C. marcescens is characterized by the conspicuous lirellae, the laterally carbonized exciple, the hyaline ascospores muriform with(12.5-20)×(5-7.5)μm size, and the presence of salazinic acid. The specimens examined come from Mt. Shengtang, Jinxiu, Guangxi. So far, only one species reported in the rare genus from China. The species was firstly found in the natural environment and inland of Guangxi, China. Which is very important to the flora study, protection and using of the species resource.

Ecological and biological characteristics of Pisonia grandis

2017/12/28 18:19:53

As a predominant and fast growth species in the Xisha Islands, Pisonia grandis (Nyctaginaceae)with important ecological, medicinal and ornamental values plays an important role in wind prevention and sand-fixation. In this study, we examined the morphological and physiological characteristics, nutrient composition of P. grandis growing on Yongxing Island, Xisha Islands. The results showed that P. grandis was a heliophyte, which was characterized with large leaf thickness, small specific leaf area, well developed palisade tissue and sparse intercellular spaces in pongy tissue. Because of these characteristics, P. grandis could obtain light energy and water effectively. The high activities of superoxide dismutase and catalase, the high content of proline, while the low content of malondialdehyde indicated that P. grandis had drought resistance. In addition, the content of nutrient elements were high for plant leaves but low for rhizosphere soil, suggesting that P. grandis was able to use nutrient elements of rhizosphere soil effectively and had strong tolerance to barren soil. P. grandis was a fast growing plant, and had good adaptability to different environments. Water and mineral nutrition should be added to improve its growth in cultivation. In a word, P. grandis can adapt to the environmental stress, such as strong light, drought and infertility. Therefore, P. grandis can be used as an important tree species of vegetation restoration in tropical coral island.

Distribution characteristics of soil organic carbon storage and carbon density from damaged vegetation under different climate types in Wenchuan earthquake region

2017/12/28 18:19:54

Taking typical regions affected by Wenchuan earthquake as research area including semi-arid dry warm river valley and subtropical humid monsoon climates, we set up the undestroyed region(UR)and destroyed and treated region(DR)as sampling plots. We determined soil water content, bulk specific gravity and organic carbon(soil organic carbon, SOC)content in different levels(0-5, 5-10, 10-20 cm). We analyzed the distribution characteristics between undestroyed region and destroyed and treated region in different climatic regions. The results were as follows:(1)SOC content of each soil layer in UR was significantly higher than that of DR in two typical climatic regions(P<0.05), while SOC increased first and then decreased with the soil depth. The SOC content in different soil layers in the same climatic region had no significant difference(P>0.05)with a fluctuated trend.(2)SOCD in UR was significantly higher than that in DR(P<0.05)and increased with the soil depth. It did not show significantly different(P>0.05)in different soil layers in the same climatic region.(3)Treatments in both climatic regions significantly influenced SOC content, but the interaction between treatments and soil layers and the influence of different soil layers was not significant(P>0.05). Different treatments and soil layers as well as their correlation significantly influenced SOCD(P<0.01), the interation between treatments and climate types was significantly different(P<0.05). The results indicate that soil organic carbon content in destroyed and treated region is lower than that in undestroyed region. Our results will supply the data for evaluating the effects of ecological restoration measures.

Distribution pattens of tree species and its influencing factors of topography in a mid-montane humid ever-green broad-leaved forest in Gaoligong Mountains

2017/12/28 18:19:54

The change features for distribution pattern of tree species under different sampling areas and growth stages to explore the influence of topographic factors on the distribution pattern of tree species were analyzed. As the mid-montane humid ever-green broad-leaved forest in the Gaoligong Mountains National Nature Reserve of Yunnan Province was taken as the research object, such approaches as diffusion coefficient, variance analysis and multiple comparison were adopted, based on the topographic data and community survey data of 200 m × 200 m dynamic monitoring plots. The results showed that the majority trees in the community exhibited aggregated distributions and a few species were randomly distributed. The distribution pattern of most tree species had nothing to do with the sampling area, most of which exhibited aggregated distributions under each sampling area; the distribution pattern of a few tree species was affected by sampling area, and they were randomly distributed in small areas and exhibited aggregated distributions in large areas. The distribution pattern of about half of the trees in the community was independent of its growth stage, most of which exhibited aggregated distributions in all growth stages. On the other hand, the distribution pattern of the other half species was affected by the growth stage: most young trees exhibited aggregated distribution, and middle trees and large trees showed random distribution. The variance analysis demonstrates that terrain heterogeneity has an important effect on aggregated distribution of most tree species, and that the differentiation of tree species in resource niche is the controlling factor, while the terrain redistribution of hydrothermal resources is an important factor.

Spermatophyte flora and its geography implication of Sanming Castanopsis kawakamii Nature Reserve

2017/12/28 0:00:00

Spermatophyte flora characteristics, from Sanming Castanopsis kawakamii Nature Reserve in Fujian Province, were analyzed and the differences among four adjacent regions were compared based on the spermatophyte list which was formulated according to specimens collection and relevant literatures. The results showed that flora origin was relatively old and maintained the original species composition that had kept a complete evolutionary series of seed plants since the Miocene. Due to its complex terrain conditions and alternate climate influence of wind belt from east and west, the species composition is abundant and consists of 1 303 species belonging to 149 families and 602 genera; the constructive species belongs to the families of Lauraceae and Fagaceae, has more complex family and genus geographic components of tropical distribution type than that of temperate distribution, and pantropical distribution has the largest proportion; by comparing with adjacent areas, the similarity with Daiyun Mountain is the highest and decreased with the movement toward north or south. Flora characteristic analysis illustrates that the spermatophyte flora, in Sanming Castanopsis kawakamii Nature Reserve, belongs to the Lingnan area but not the East China. Plants flora, in this area, belong to the Eastern Asiatic region, Sino-Japan forest subregion, Lingnan region, and North Guangdong subregion. The distribution of family, genus, species and specific degrees are discussed among. South Zhejiang subregion controlled by C. scleiophylla, North Fujian subregion, North Guangdong region and East Nanling subregion controlled by C. hystrix, North Fujian subregion neither controlled by the two species.

Ipomoea wrightii A. Gray a newly naturalized species in mainland of China

2017/12/28 0:00:00

Ipomoea wrightii A. Gray, is recently found to be naturalized in Zhanjiang, Guangdong, China, which is native to tropical America, introduced and naturalized in Taiwan, China. Morphological variations of this species were carefully examined and habitat information were also collected during field investigation. Detailed description and color photographs are provided for the facility of identification. Their potential ecological risks are also discussed.

Age structure and population dynamics of dominant species in a Betula platyphylla—Larix olgensis forest on swamp ecotone

2017/11/29 16:58:45

In order to reveal the trend of population development and provide the basis for swamp ecotone population's recovery and management, we studied dominate species in a Betula platyphylla—Larix olgensis forest on swamp ecotone, elaborated its current situation and quantity dynamic, by adopting space as substitute for time, and taking trunk size structure in place of age structure, study on age structure of the dominate species in a Betula platyphylla—Larix olgensis forest. Based on the life table of population and the theory of survival analysis, we worked out the life table of Betula platyphylla, Larix olgensis and Alnus hirsuta population and estimated the survival curve, mortality curve, as well as other important parameters. Population dynamics were analyzed by using dynamic quantitative index, spectral analysis and time-sequence model. The results showed that the age structure of Betula platyphylla and Larix olgensis population were spindle type, Lognormal function can represent the relationship between age and number of individuals. Dynamic index V'_pi with the order of Alnus hirsuta(9.57%)> Betula platyphylla(4.02%)> Larix olgensis(1.83%), the populations tend to be stable, and the populations enter the transition phase of recession. The mortality was high in early stage, the number of saplings was gravely insufficient. The survival curve of the Betula platyphylla and Alnus hirsuta population indicated that it approached a Odum-B₃type, however, the survival curve of the Larix olgensis revealed that it approached a Deevey-I type; Four survival functions curves suggested that the Betula platyphylla, Larix olgensis and Alnus hirsuta population would have an early increase then recession in mid to late-stage. Spectral analysis of the population demonstrated that the first harmonic have a significant on the dynamic of population,there was not a marked periodic fluctuation in the progress of natural regeneration of Betula platyphylla, Larix olgensis and Alnus hirsuta, the development of whole population trend to stability; The time sequence model predicted that the number of old age individuals would ascent in the coming two, four and six age classes in Betula platyphylla, Larix olgensis and Alnus hirsuta populations, but the regeneration seedling was rare, so the population tend to degenerate are inevitable. Forest-swamp ecotone are more sensitive and vulnerable to environment change, humanactivities have a significant impact on the development and evolution of Betula platyphylla, Larix olgensis and Alnus hirsuta populations, which improve the risk of forest transition into swamp, therefore, we should minimize disturbance and strengthen the protection and management of vegetation communities on forest-swamp ecotone, so as to create favorable conditions for the succession of forest-swamp ecotone communities to forest.

Spatial heterogeneity of soil organic carbon under different forest types across Guangxi

2017/11/29 16:58:45

By combination of classical statistics, geostatistics and geographic information system, the spatial heterogeneity of soil organic carbon(SOC)in different layers(0-10, 10-20, 20-30, 30-50 and 50-100 cm)of ten kinds of major forest types in Guangxi were studied. Soil samples were collected from 115 sampling locations and 345 plots(50 m × 20 m), according to 10 km × 10 km grid. The results showed that the average content of SOC in different forests in Guangxi ranged from 8.01 to 29.78 g·kg^-1 and the coefficient of variation(CV)ranged from 50.27% to 74.89%. The semivariagram of SOC in 10 - 20 cm soil layer was best fitted with exponential model whereas those in other soil layers were best fitted with spherical model. The nugget effect of semivariagram of SOC in all soil layers ranged from 16.75% to 49.33%, indicating a strong or a moderate spatial autocorrelation. Kriging interpolation results showed characteristics of spatial distribution of SOC in different soil layers were similar, i.e., higher in the north while lower in the south, and the maximum and minimum occurred in the northeast and the southeast of Guangxi, respectively. The average of SOC and its CV varied with forest type and soil layer, and the average of SOC in 0 -100 cm layer followed the order: Castanopsis > Cunninghamia lanceolata > Cyclobalanopsis glauca > Liquidambar > Bambusa multiplex > Octagon > Eucalyptus > Camellia oleifera > Quercus > Pinus. On the whole, SOC decreased with increasing soil depth, while the CV exhibited an opposite trend. The spatial heterogeneity of SOC in forest of Guangxi was synthetically influenced by structural and human factors, while the structural factors played a dominant role. It is suggested that expanding the area of natural forests and plantations like Cunninghamia lanceolata while reducing the area of Eucalyptus and certain economic forests like Camellia oleifera will help increase carbon sequestration potential in forest of Guangxi.

Diversity and floristic characterics of Orchidaceae in Hubei

2017/11/29 16:58:45

Vegetation of Hubei is a hotspot of biology study, especially in the western mountains, which is a center of biodiversity in China. On the basis of specimen data, literature and field survey findings, a list of the Orchidaceae in Hubei was developed. The characteristics of the Orchidaceae distribution pattern in Hubei, geographical flora and diversity were analyzed, based on the topographic and climatic features of Hubei. Orchidaceae in Hubei is distributed mainly in southwest, northwest, northeast and southeast mountain areas. Its diversity is the highest in western mountains especially in the areas at the altitude of 900 - 1 200 m while the lowest in Jianghan Plain in central South Hubei. Generally the species richness decreases from the west to the east and from the south to the north. The diversity similarity between southwest and northwest mountains is the highest. There are 141 species, belonging to 54 genera, 15 subtribes, and 5 subfamilies except for subfam. Apostasioideae. Overall, 50.00% of the genera are monotypic, and 33.33% are oligotypic. The florescence is mainly in April to September, and July is the peak of flowering. Among all the species found in Hubei, 40.43% are East-Asian species, and 41.84% are endemic to China. Twenty-five genera are tropical, meanwhile 27 are temperate, with a ratio of 0.93. The tropical species account for 8.51%, and the temperate species account for 91.49%. The study showed that among the Orchidaceae in Hubei, the Eastern Asian flora was the main part, and the Sino-Japanese type was dominant. At the same time, Orchidaceae in Hubei showed high temperate attribute and significant characteristics of the transition between the sub-tropics and the temperate zone. The disjunctive distribution of some rare species in Hubei and Taiwan of China indicates a considerable correlation between the flora of the two areas. Hubei is closely related to Southwest China and the Hengduan mountains in respect of the Orchidaceae flora, and Hubei is the transitional area for the flora exchange with the East China.

Passiflora morifolia, a newly naturalized plant of Passifloraceae from China

2017/11/29 16:58:45

Naturalization and invasion of alien species have made great impact on the global environment and social development, and have become global issues of biodiversity management and ecological protection. China is regarded as one of the countries that are the mostly threatened by biological invasion in the world, and faces severe challenges in the early warning, supervision and management of invasive alien species. Passiflora morifolia Mast., a newly naturalized plant of Passifloraceae from China, is reported in this article, its morphological description and related photos are provided too. P. morifolia is native to the tropical regions of central and South Americas, and was newly found in Menglian County, Yunnan Province, Southwest China. It is characterized by its leaves herbaceous, three palmately lobed, with sparsely short bristles, stipules ovate, semi-amplexicaul, cymes degenerate, bracts linear, with 1-2 flowers, pedicels 3-6 cm long, petals white, coronal purple at base, mature fruits purple, with short bristles and frost. In Chinese species, P. morifolia is the most similar to P. foetida, but the latter is with spreading pubescent and glandular hairs, petioles without glands, inflorescence bracts 1-3 pinnatifid, corona often pink at base. In additon, its potential harm and invasive risks are briefly assessed.

Changes of bacterial flora structure in rhizosphere soil of soybean at different growth stages

LIU Xin, LI Zhiying, LIU Ruirui, LI Lulu, WANG Weiwei — 2018/10/28 18:24:41

Soybean rhizosphere soils at seedling and mature stages were collected in this experiment as the research material, and Illumina high-throughput sequencing technology was used to determine the 16S rDNA V3+V4 region sequence of bacteria, in order to understand the diversity of bacterial community structure and the changes of bacterial community structure in soybean rhizosphere.The original Tags data were used by splicing, filtering, removal of chimeric sequences and cluster analysis of data processing, OTU taxonomic annotation. On this basis, the changes of species composition were analyzed by ANOVA method, and the diversity of bacterial composition was also studied by alpha diversity index. The results showed that there was a significant change in the abundance and diversity of bacteria at different growth stages. Diversity index analysis showed that the abundance and diversity at mature stage was significantly higher than seedling stage in soybean rhizosphere soil. Species composition analysis results showed that Proteobacteria, Actinobacteria and Acidobacteria are the dominant rhizosphere bacteria at phylum level and their contents in different growth stages also significantly increased. ANOVA analysis showed that the abundances of Proteobacteria and Acidobacteria were significantly different, but Actinobacteria was not significantly different at different growth stages. Pseudonocardia, Saccharomyces and Sphingomonas were the dominant genra in the rhizosphere of soybean. Some of these genera belonged to plant growth-promoting rhizobcteria and had the potential capacity for promoting growth. These results confirm that the growth period of soybean has an important influence on the bacterial community structure in rhizosphere soil.

Community structures and biodiversities of broad-leaved forest and two types of plantations in Gutianshan National Nature Reserve, Zhejiang Province

2018/10/28 18:24:42

In order to understanding how the community structure, species composition and diversity differ between different forest types, we investigated and compared the community structure and biodiversity for one natural forest type(i.e. broad-leaved forest)and two types of plantations(i.e. Cunninghamia lanceolata assemblage/stand and Camellia oleifera assemblage/stand)in Gutianshan National Nature Reserve of Zhejiang Province. The results were as follows:(1)In general, broad-leaved forest held the highest taxonomic diversity, followed by Camellia oleifera stand and Cunninghamia lanceolata stand. With respect to different forest layers, broad-leaved forest held the highest species richness in tree and shrub layers and Camellia oleifera stand held the lowest; C. oleifera stand held the highest species richness in herb layer, followed by Cunninghamia lanceolata stand and broad-leaved forest. On the other hand, species composition of the top five(according to species importance value)species differed greatly both between forest types and forest layers.(2)At the single forest plot level, difference in α diversity of the three stand types was mainly in tree layer, shown as broad-leaved forest held the highest α diversity and Camellia oleifera stand held the lowest; no difference was detected in shrub layer; whereas C. oleifera stand held the higher species richness in herb layer.(3)As for β diversity between forest types, the greatest difference in species composition was between broad-leaved forest and C. oleifera stand, followed by between broad-leaved forest and C. oleifera stand, and between C. lanceolata stand and Camellia oleifera stand, in shrub layer; species composition between broad-leaved forest and Cunninghamia lanceolata stand had more differences than between C. lanceolata stand and Camellia oleifera stand, in herb layer. The results imply that each of the three forest types hold its unique community structure and biodiversity, which contributes to the landscape level biodiversity, and testify the influence of human disturbance.

Screening of submerged macrophytes for phytoremediation of cadmium-contaminated water in Baiyangdian Lake

2018/10/28 18:24:42

In order to screen the suitable submerged macrophytes for phytoremediation of cadmium(Cd)-contaminated water in Baiyangdian Lake, which is the largest freshwater lake in North China, indoor simulation experiments were conducted to investigate the tolerance of Cd, and accumulation and transportation of Cd from contaminated sediment by four kinds of submerged macrophytes which were Hydrilla verticillata, Myriophyllum verticillatum, Ceratophyllum demersum and Potamogeton crispus. The results were as follows:(1)Results of the toxicity test showed that 4 d-EC₅₀ of Cd for Hydrilla verticillata, Myriophyllum verticillatum, Ceratophyllum demersum and Potamogeton crispus were 0.51, 0.81, 0.03 and 0.12 mg·L^-1, respectively. The tolerance for Cd from high to low was Myriophyllum verticillatum, Hydrilla verticillata, Potamogeton crispus and Ceratophyllum demersum. Myriophyllum verticillatum showed the strongest tolerance for Cd. In addition, the maximal concentrations of Cd for Hydrilla verticillata, Myriophyllum verticillatum, Ceratophyllum demersum and Potamogeton crispus were 27.89, 15.28, 22.54 and 32.74 g·kg^-1, respectively. Potamogeton crispus had the strongest accumulation capability of Cd, followed by Hydrilla verticillata, and Myriophyllum verticillatum had the lowest.(2)The results of remediation Cd-contaminated sediment by Hydrilla verticillata, Myriophyllum verticillatum and Potamogeton crispus indicated that accumulation of Cd in roots was significantly higher than that in leaves and stems(P<0.05). Furthermore, concentrations of Cd in shoots of submerged plants decreased in order of Hydrilla verticillata > Potamogeton crispus > Myriophyllum verticillatum, while contents of Cd in roots decreased in order of Potamogeton crispus > Hydrilla verticillata > Myriophyllum verticillatum. Moreover, the transportation capability of Cd from Cd-contaminated sediment to plants in the pattern of Hydrilla verticillata > Myriophyllum verticillatum > Potamogeton crispus. In summary, due to the higher tolerance, accumulation and transportation ability of Cd, Hydrilla verticillata is the most suitable submerged macrophyte for remediation of Cd-contaminated water in Baiyangdian Lake.

Responses of reproductive traits and biomass allocation in Delphinium kamaonense var. glabrescens at flowering stage to grazing

2018/10/28 18:24:42

Biomass allocation influences many aspects of plant growth and reproduction, and is a major element in the research of plant life history. Focusing on Delphinium kamaonense var. glabrescens, a weed in the alpine meadow on the Qinghai-Tibet Plateau, we studied the influence of grazing on the reproductive and sexual allocation at flowering stage. The results showed that grazing significantly affected the total above-ground biomass, vegetative biomass and reproductive biomass of the plant. There was an isometric scaling relationship between the vegetative and the reproductive biomass, and grazing significantly increased reproductive allocation. There was a significant positive correlation between the individual size and the total number of flowers, but a significant negative correlation between vegetative biomass and sexual allocation. Grazing had no significant effects on sexual allocation. There were significant negative correlations between the total number of flowers and single flower size, and the total number of flowers and the proportion of flower petals in a single flower. These results indicated that there were trade-offs between the total number of flowers and single flower size, and between the total number of flowers and the proportion of flower petals in a single flower. Both reproductive and sexual allocations showed significant plasticity in response to grazing

A newly recorded species of Cyperus from China

2018/10/28 18:24:42

Cyperus hakonensis Franch. & Sav., a newly recorded species of Cyperus from China was reported in this paper, Chinese description of the species was enriched and its anatomy figure was also supplemented. Its spikelets are palegreen, about 2 mm wide. Glumes are thin and transparent on both surfaces but keel abaxially palegreen, apex with a recurved awn, nutlet smooth, shiny. The voucher specimen was deposited in Herbarium of Shandong Drug and Food Vocational College(SDFH).

Responses of litter CO₂emission to simulated acid rain in a mixed conifer and broad-leaved forest of Dinghushan Nature Reserve

2019/4/1 11:15:23

A field experiment of simulated acid rain(SAR)was conducted in a mixed conifer and broadleaf forest(MF)at Dinghushan Nature Reserve. SAR treatments included CK(the local lake water, pH 4.5), T1(pH 4.0), T2(pH 3.25), and T3(pH 2.5)with four replicates. SAR experiments were initiated in January 2011, and the litter CO₂ emission rate under SAR was measured twice a month over one year from January 2013 to December 2013. The results indicated that litter CO₂ emission followed a clear seasonal pattern in the forest during the study period, with significantly higher rates in the wet season and lower rates in the dry one(P<0.05). The mean annual litter CO₂ emission in the CK plots was(1 507.41±155.19)g CO₂·m^-2·a^-1, to which the wet season and the dry season contributed 68.7% and 31.3%, respectively. SAR significantly reduced litter CO₂ emission in the forest(P<0.05). Compared with CK, mean annual litter CO₂ emission was 15.4% and 42.7% lower in T2 and T3 treatments, respectively. SAR reducing litter CO₂ emission had seasonal differences, and these negative effects were evident in the wet season(P<0.05), but not in the dry one. In all treatments, litter CO₂ emission rate exhibited significantly positive exponential relationships with soil temperature and significantly positive linear relationships with soil moisture. In addition, the mean temperature sensitivity(Q₁₀)values showed a declining trend with the increasing level of SAR. The depression of litter CO₂ emission after SAR in the MF was related to the aggravation of soil acidification and the depression of microbial activity, as we found that soil pH value and soil microbial biomass C significantly decreased under SAR. In conclusion, our results supported an important role of acid rain in regulating soil carbon cycle.

Population dynamics of Schima superba in a lower subtropical evergreen broad-leaved forest

2019/4/1 0:00:00

Schima superba is a dominant species in the lower subtropical evergreen broad-leaved forest community at Dinghushan. In order to understand the construction mechanism of lower subtropical evergreen broad-leaved forest community, we have established a 20 hm² forest biodiversity monitoring plot at Dinghushan National Nature Reserve. The data presented in this paper are based on four field investigations of all S. superba individuals from 2005 to 2017. We further analyzed the distribution characteristics of its death rate according to diameter class and habitat type. The results were as follows:(1)The number of S. superba individuals was largely reduced from 2005 to 2017.(2)Mortality rate and growth rate of S. superba showed different patterns depending on diameter class. The relative growth rate of the individuals of 1-10 cm DBH was high and rapidly decreased, while the mortality rate increased and maintained at a high level. With the increase of DBH class, the relative growth rate of the individuals of 10-50 cm DBH rose and decelerated, and then decreased, while the mortality rate decreased. The mortality rate of those individuals above 50 cm DBH was large while the growth rate was little.(3)The mortality rate of the individuals in each habitat in 2010 was not apparently different. However, in 2015, the mortality rate of individuals in high-altitude habitats(high slopes, ridges, and valleys)was greater than those in low-altitude habitats(low slopes and valleys), while those in low-altitude habitats in 2017 were higher than those in the high-altitude habitats.(4)The mortality rate was significantly positively correlated with soil pH and negatively correlated with soil organic matter, total nitrogen, total phosphorus, available potassium, and available nitrogen content.

Dynamics patterns of extractable humus carbon from newly-shed litter of four tree species at different phenological stages in the Rainy Area of West China

2019/4/1 11:30:15

The extractable humus carbon of the litter can change with the rhythm of the plant growth and the phenological period, and then affect the material circulation process. In order to fully understand the features of the litterfall-supported regional ecosystem cycle, Quercus acutissima, Phoebe zhennan, Cryptomeria fortune, and Camptotheca acuminatain were selected in the Rainy Area of West China. Different types of litters in the leaf budding period, leaf expanding period, leaf maturing period, and leaf falling period were dynamically collected through fixed-point analysis of the differences in the extractable humus carbon(HC), humic acid carbon(HAC), fulvic acid carbon(FAC), and humic acid carbon/fulvic acid carbon(HAC/FAC). The results were as follows: The contents of HC and HAC in leaf litter were the highest in the same critical period, and they all showed as leaf litter> twig litter> fruit litter, and also showed that the evergreen tree species was not significant but the deciduous tree species was significant; Compared with other periods, leaf litter of the four tree species exhibited high FAC content during the leaf expanding period, However, HAC content and FAC content of twig litter and fruit litter in phenological stages are greatly affected by species. Humic acid carbon/Fulvic acid carbon(HAC/FAC)in leaf litter of four tree species to characterize the relative content and formation rate of humic acid, fulvic acid during the humification of leaf litter, there was no significant difference between organs, showing that the deciduous tree species had lower HAC/FAC than evergreen tree species. The present study indicates that stage types, species types, organ types and their interactions have different degrees of influence on HC, HAC, FAC content and HAC/FAC in litter. The results provide a theoretical information and a new direction for further understanding the material circulation process of litterfall in the regional ecosystem.

Spatial distribution pattern and quantitative dynamics of the endemic plant Camellia rubituberculata in Guizhou Province

2019/10/25 14:38:22

Camellia rubituberculata is endemic to Guizhou Province with narrow geographical distribution and has economic value. In order to find out its distribution characteristics and evaluate its endangered status, three typical sample plots were set up in concentrated areas, and the spatial distribution pattern of population was analyzed by spatial dot pattern and multivariate point pattern analysis, the quantitative index analysis of population dynamics was used to predict the dynamic law of population quantity. The results were as follows:(1)The young trees in Dapipo sample plot 1 showed cluster distribution in small-scale and random distribution in large-scale, and the distribution of middle-aged trees and old-aged trees in all scales were random. The young trees in Caozitu sample plot 2 were clustered at all scales, the middle-aged trees and the old-aged trees were random. The young trees, middle-aged trees and old-aged trees were randomly distributed in Shangpengbi sample plot 3.(2)The spatial correlations of different developmental stages mainly manifested that the young and middle-aged trees in sample plot 1 were negatively correlated at all scales, the young trees and old-aged trees were negatively correlated at medium and small scale, and there were no correlation in the large scale. The middle age trees and the old-aged trees were not related at all scales. In sample plot 2, there was negative correlation between young trees and middle-aged trees at small scale and no correlation at medium and large scales, young trees and old-aged trees were negatively correlated at medium and small scales, but not at the medium and large scales, there was no correlation between middle-aged trees and old-aged trees at all scales. The young trees and middle-aged trees in sample plot 3 were positively correlated at all scales; there was a negative correlation between young trees and old-aged trees on the small scale, but no correlation on medium scale, and positive correlation on the large scale; the middle-aged trees and old-aged trees were irrelevant at all scales.(3)The population quantitative dynamic analysis indicated that the seedlings in the three sample plots were well supplemented, and the population structure was growth type, but they were vulnerable to environmental disturbance and ecological fragility.(4)The results of habitat heterogeneity and interspecific interaction of C. rubituberculata are the main factors affecting population expansion and species dispersal.

Landscape pattern analysis of urban forest in central Beijing

2019/10/25 14:38:22

Urban forest is one of the most important ecological development in the urban area of a city. Taking the urban forest in central Beijing as research object, we divided it into four types of urban forest according to its ecological service function, including subordinated landscaping forest, road river shelter forest, city park leisure forest and suburban recreation forest. Extracting four types of urban forest using object oriented method and transformed into thematic maps based on GF-2 high-resolution images on September 16, 2016. Then we analyzed the number of patches, patch constitution, fragmentation index, Simpson's diversity index, Simpson's dominance index and aggregation index with Fragstats 4.2 software. The results suggested superiority of high resolution remote sensing data, about 32.35% area of central Beijing were covered by urban forests total area being 22 514.79 hm², about 13.62% of all patches were large patches with area being 73.20%. Unbalanced and irrational distribution on different positions and rings, subordinated forest and road river shelter forest were the dominant landscapes, however, with high fragmented landscape and low aggregation index, the other two kinds of landscapes took small proportion, especially poor in South Beijing. Besides the fragmentation level reduces from the second ring road to the fifth ring road, with the highest fragmentation pattern in the second ring about 183.50. Based on these results, suggestions are promoted as follows, making full use of small patches and build pocket park, strengthening the construction of road river shelter forest in order to connect city park forest and suburban recreation forest, increasing urban forest coverage within the third ring road and improving the quality of urban forest outside the third ring road.

Species composition and distribution pattern of Elatostema(Urticaceae)in Guizhou

2019/10/25 14:38:23

Elatostema (Urticaceae)is one of the recognized taxonomic groups in the field of plant taxonomy because of the wide variety and similar morphology and close relationship. The geographical location of Guizhou Province is special, the water and heat conditions is better. The karst landforms are complex and changeable. It is an important distribution area of the Elatostema. But the species is unclear and the classification is unknown. In order to further clarify the resource and distribution characteristics of Elatostema. This list forms recent surveys and access to statistics. Analysis of species composition and spatial characteristics were based on species distribution and elevation data. It is hoped that this reseach will provide further basic information for Guizhou plant species diversity protetion and related floristic study. The results are as follows: Pellionia groups have seven species from one system in one group and Elatostema groups have 69 species from 20 system in five groups. They account for 17.94% and 20.78% of the national species in China. Elotostema has 76 species in total, among which 13 species are endemic to Guizhou. In the geographical distribution, Pellionia groups are mainly distributed in parts of North Guizhou-East Guizhou-South Guizhou. Along the lines of Chishui, Tongzi, Xishui, Zhengan-Jiangkou, Yinjiang-Jianhe-Duyun and Libo-Wangmo, showing an opposite of “C” shape. Elatostema groups are mainly distributed in most areas of North Guizhou-East Guizhou-South Guizhou-Southwest Guizhou. Along Chishui, Zhengan, Jiangkou-Qixingguan, Kaiyang, Shibing, Huangping-Xingyi, Xingren, Anlong, Zhenfeng, Wangmo, Dushan and Libo, showing a Chinese character “Three” shape, like three short parallel lines. The endemic of Elatostema are generally point-like and unevently distributed. The genus is mainly distributed in the range of 600 -1 000 m.

Changes of allometric relationships among leaf traits of Disanthus cercidifolius var. longipes in different ontogenetic stages and altitude gradients

2019/10/25 14:38:23

Disanthus cercidifolius var. longipes is a rare and endangered plant distributed only in the southeast area of China. In order to research the allometric relationship of leaf trait, characteristic of leaf resource utilization, and their changes with ontogenetic development and altitude gradient, we investigated and analyzed allometric relationships among the lamina mass, lamina area, lamina volume and lamina water content of D. cercidifolius var. longipes plants at different developmental stages in D. cercidifolius var. longipes communities distributed along altitude gradient in Jiangxi Province. The results showed that there were significant different allometric relationships among plants at different deve-lopmental stages. The increasing rate of lamina area was lower than or equal with that of lamina mass in adult trees, meanwhile the growth rate of lamina area was lower than that of lamina mass in saplings and seedlings; The lamina vo-lume and lamina mass of adult trees grew at the same rate, but the lamina volume of saplings and seedlings grew faster than the lamina mass of them; The growth rate of lamina water content was slower than that of lamina mass in adult trees, meanwhile the growth rate of both characters grew at the same rate in saplings and seedlings. Altitude gradient also influenced the allometric relationship among leaf traits. The allometric relationships between the lamina volume, lamina water content and lamina mass differed significantly among altitude gradients. At the low elevation, the lamina volume and lamina mass grew at the same rate, meanwhile lamina water content grew slower than lamina mass. At the high elevation, the lamina volume grew slower than lamina mass, and the lamina water content and lamina mass grew at the same rate. These results suggested that the investment strategy of leaf resources of D. cercidifolius var. longipes changed with the change of ontogenetic development and altitude gradient. The adult trees of D. cercidifolius var. longipes invested more lamina biomass in the development of light-harvesting area and assimilation structure, meanwhile the saplings and seedlings mainly invested lamina biomass in the development of vascular tissue. As the increase of altitude would increase wind and light intensity, and change physicochemical properties, D. cercidifolius var. longipes plants tends to increase the lamina volume to capture more resources at the middle and lower altitudes, and tends to strengthen the construction of machinery and vascular tissue to resist external interference at the higher altitude.

Modeling geographical distribution pattern and comparison of ecological characteristics between Cerasus cerasoides and C. campanulata

2019/10/25 14:38:23

BIOCLIM model was used to simulate the range of modern suitable areas by collecting the geographical coordinates of its actual distribution and predict the change of their potential distribution under climate change(CCM3)for 2 100 s. The dominant climatic factors were determined by principal component analysis and correlation analysis. The differences between two species in climate limiting factors were analyzed. In addition, the receiver prediction effect was evaluated using the receiver operating characteristic(ROC). The results were as follows:(1)The actual distributions of C. cerasoides and C. campanulata covered most areas of the South of the Yangtze River in China. The contemporary distribution centers were located in the Yunnan-Guizhou Plateau, the Wuyi Mountain Range and the Nanling Mountains.(2)Under the future climate change situation(CCM3), the range of potential suitable areas of C. cerasoides and C. campanulata would decrease. The suitable habitat in Southwest(C. cerasoides)and Southeast China(C. campanulata)would be significantly reduced, while that of C. campanulata in West Hunan would increase.(3)Principal component analysis(PCA)and correlation analysis indicated that the annual precipitation(bio12), precipitation of the driest quarter(bio16), precipitation of the warmest quarter(bio18)and temperature seasonality(bio4)were the major factors influencing the geographical distribution of C. cerasoides and C. campanulata. “Radiator variability” was the most important environmental factor causing the difference in the distribution of two species.(4)Both of the AUC values of C. campanulata(0.816)and C. cerasoides(0.799)were higher than that of random test(0.500), which indicated that the BIOCLIM model could accurately predict the distribution of C. cerasoides and C. campanulata. Our results will be an important guide for the study of conservation, identification and phytogeography of C. cerasoides and C. campanulata.

Centratherum Cass., a newly naturalized genus of family Asteraceae from mainland of Southeast Asia

2019/10/25 14:38:23

Centratherum Cass., a newly naturalized genus of the family Asteraceae from Southeast Asia, was recorded in North Thailand and Southwest China. C. punctatum Cass. Subsp. fruticosum(S. Vidal)K. Kirkman ex Shih H. Chen, M. J. Wu & S. M. Li, the only one representative subspecies of this genus from mainland of Southeast Asia, is described and illustrated based on the specimens. C. punctatum Subsp. fruticosum can be distinguished from the other taxa of this genus by its leaf blade rhombic to elliptic, leaf margins irregularly serrate, leaf apex broadly acute, and phyllaries indurate at base and not awned. Its distribution map is provided and the possible dispersal pathway is discussed.

Two newly recorded genera of Poaceae from Guangxi,China

2019/10/25 14:38:23

Beckmannia Host and Tripogon Roem. et Schult. of Poaceae are reported as two newly recorded genera from Guangxi, China. There are two species and one variety of Beckmannia in global, which are widely distributed, including one species and one variety in China. A species, B. syzigachne(Steud.)Fern. is found from Guangxi for the first time. There are about 30 species of Tripogon in global, and majority species are distributed in Asia and Africa, including eleven species in China. A species, T. filiformis Nees ex Steud. is found from Guangxi for the first time. Detailed morphological description and photos of the two newly recorded genera and species are provided in this paper.

Amaranthus powellii S. Watson and A. bouchonii Thell., two newly naturalized species in China

2019/10/25 14:38:23

About twenty Amaranthus species have been recorded in China and most are alien weeds. The morphological characteristics are similar under genus, and often occurrring misidentifications. We found two newly alien species from submitted specimens which were identified as another species. Two Chinese epithets were entitled separately by the Latin names of specific meaning. Amaranthus powellii S. Watson and A. bouchonii Thell., two invasive plants from Southwest USA and Europe separately, are similar on morphology, monoecism, pistillate flowers with 3-5 unequal tepals, equal or short of utricle, utricle dehiscence or indehiscence. Both of them can be distinguished by numbers and shapes of tepals, features of utricles, and shapes and sizes of bracts. In this paper, their Chinese description, color illustrations, key features and distribution and harmful status are provided as well.

New additions to the bryophyte flora of Shandong Province, China

2019/10/25 14:38:23

Dichodontium pellucidum (Hedw.)Schimp. and Fauriella tenuis(Mitt.)Cardot are reported as new records to Shandong Province, China. At the same time, the family Aongstroemiaceae and the genera Dichodontium Schimp. and Fauriella Besch. are also found from Shandong Province for the first time. Detailed descriptions and ink drawings of Dichodontium pellucidum (Hedw.)Schimp. and Fauriella tenuis(Mitt.)Cardot are given, while brief discussions are provided.

-->Plant Ecology and Geography

Water ecological amplitude of Phalaris arundinacea at rhizomatic germination and seedling stage

Vertical distribution of bryophytes in Yueliang Mountain Nature Reserve

Two newly recorded genera of angiosperm from Guangxi

Responses of soil microbial biomass, community structure and soil enzyme to below-ground carbon change in the warm-temperate forest ecosystem

Interspecific associations between south subtropical forest plant community species in Daqingshan of Guangxi

Comparing the water use efficiency of plants in different types of rubber-based agroforestry ecosystem in Xishuangbanna, Southwest China

Estimating the carbon storage of Fuyang forest ecosystems based on InVEST model

Evaluation of ecosystem services in the small-scale forest in suburban

Distribution and community characteristics of threatened seagrass Halophila beccarii in Dongzhai Harbor, Hainan

Effects of ecological factors on anther dehiscence of Paris polyphylla var. yunnanensis

Relationship between stem flow of flowering jujube and meteorological factors

Characteristics of soil respiration components in the Quercus aliena var. acuteserrata forest chronosequence

New records of lycophytes and ferns from Shandong Province

Structure and dynamic characteristics of wild longan population in Dongfang City, Hainan

Pollination biology of Aspidistra retusa

Coenological characteristics of Pseudotsuga sinensis forests in Qizimei Mountains Nature Reserve

Analysis on community stability and inter-specific correlations among dominant woody populations of the endangered plant Sinojackia rehderiana communities

New records of ferns from Guangxi, China(Ⅱ)

Analysis on vertical distribution pattern of flora of seed plants in Kuche

Impact factors of the total flavonoid contents in Guizhou miao medicine Laportea bulbifera based on grey correlation analysis

Characteristics of the accumulation of heavy metals in the leaves of six common green tree species and its correlation with environment factors in Hangzhou City, China

C, N and P ecological stoichiometry of two bryophyte plants in Baotianman Nature Reserve

Effects of soil moisture on the ecophysiology of moso bamboo (Phyllostachys edulis)in upper reaches of Lijiang River

New records of angiosperms in Gansu Province

A new combination of Phyllolobium (Leguminosae)from China

Gastrodia punctata Aver., a newly recorded species of Orchidaceae from China

Carbacanthographis (Graphidaceae), a lichen genus new to Guangxi

Ecological and biological characteristics of Pisonia grandis

Distribution characteristics of soil organic carbon storage and carbon density from damaged vegetation under different climate types in Wenchuan earthquake region

Distribution pattens of tree species and its influencing factors of topography in a mid-montane humid ever-green broad-leaved forest in Gaoligong Mountains

Spermatophyte flora and its geography implication of Sanming Castanopsis kawakamii Nature Reserve

Ipomoea wrightii A. Gray a newly naturalized species in mainland of China

Age structure and population dynamics of dominant species in a Betula platyphylla—Larix olgensis forest on swamp ecotone

Spatial heterogeneity of soil organic carbon under different forest types across Guangxi

Diversity and floristic characterics of Orchidaceae in Hubei

Passiflora morifolia, a newly naturalized plant of Passifloraceae from China

Changes of bacterial flora structure in rhizosphere soil of soybean at different growth stages

Community structures and biodiversities of broad-leaved forest and two types of plantations in Gutianshan National Nature Reserve, Zhejiang Province

Screening of submerged macrophytes for phytoremediation of cadmium-contaminated water in Baiyangdian Lake

Responses of reproductive traits and biomass allocation in Delphinium kamaonense var. glabrescens at flowering stage to grazing

A newly recorded species of Cyperus from China

Responses of litter CO2 emission to simulated acid rain in a mixed conifer and broad-leaved forest of Dinghushan Nature Reserve

Population dynamics of Schima superba in a lower subtropical evergreen broad-leaved forest

Dynamics patterns of extractable humus carbon from newly-shed litter of four tree species at different phenological stages in the Rainy Area of West China

Spatial distribution pattern and quantitative dynamics of the endemic plant Camellia rubituberculata in Guizhou Province

Landscape pattern analysis of urban forest in central Beijing

Species composition and distribution pattern of Elatostema(Urticaceae)in Guizhou

Changes of allometric relationships among leaf traits of Disanthus cercidifolius var. longipes in different ontogenetic stages and altitude gradients

Modeling geographical distribution pattern and comparison of ecological characteristics between Cerasus cerasoides and C. campanulata

Centratherum Cass., a newly naturalized genus of family Asteraceae from mainland of Southeast Asia

Two newly recorded genera of Poaceae from Guangxi,China

Amaranthus powellii S. Watson and A. bouchonii Thell., two newly naturalized species in China

New additions to the bryophyte flora of Shandong Province, China

Responses of litter CO₂emission to simulated acid rain in a mixed conifer and broad-leaved forest of Dinghushan Nature Reserve